1. Field of the Invention
This invention relates to an endless conveyor and more particularly to vertical, spiral conveyors that may be constructed of modular frames to varying heights as determined by the number of modular frames employed.
2. Description of the Prior Art
Vertical conveyors that provide a continuous, spiral conveying surface are known in the prior art. Such devices may include a flat, continuous belt driven from a common power source at spaced points along its length, the belt returning upon itself as shown in U.S. Pat. No. 2,267,970.
Vertical spiral conveyors may also be of the chain type in which flight attachments forming the conveying surface are secured to a continuous roller chain as shown in U.S. Pat. Nos. 2,564,533 and 2,911,091. As shown in U.S. Pat. No. 3,904,025, assigned to the same assignee as this patent application, continuous chain type conveyors may be attached to stacked, modular frames permitting the construction of conveyors of different heights. All of such prior art devices however are subject to the limitation of requiring a single, continuous conveyor surface.